How Car Software Can Rig a Test – Wall Street Journal

Car makers woo customers with promises of speed, acceleration and braking distance. Less sexy is the increasingly critical element that helps them deliver that performance: software.

In the case of Volkswagen AG, it was software that the U.S. Environmental Protection Agency says allowed about 500,000 U.S.-sold Volkswagen-made cars to pass emissions tests.

Volkswagen said on Tuesday as many as 11 million vehicles may have the…